Hey, Don.
Don't put Conus textile and marmoreus in the same tank! They have
a blood feud that must go back a million years. All other shells
are ignored and the textile will go for the marmoreus... and vice
versa. In cases of equal size, the textile usually wins. But the
victor doesn't always eat the vanquished!
Both of these criters show a fondness for cowries but also for certain
other cones, with Conus flavidus high on their list of tasty treats.
These were some of my Conus observations from when I kept a couple
of aquariums of cones for cleaning shells.
Aloha,
makuabob (a.k.a. Bob Dayle)